most influential person in the 20th Century

<<GUTENBERG, JOHANNES, or Henne, who is regarded as the inventor of the art of employing movable types in printing, was born near the close of the 14th century, at Mainz.

Yes, but his influence in the 20th Century is what I am trying to determine

If that is your interpretation ....It is true that "printing" was a significant advance on "writing" but the latter is the major concept because it allowed centralized control by distribution of written edicts. Neither seems to particularly seminal to the 20th Century which has surely been influenced most by (a) mass broadcasting (b) information technology and (c) global travel. (Education per se is always subservient to a political agenda like "training workers" and world literacy rates are still poor).

Gutenberg is the most influential person in the last half millenium, IMHO.
His influence on the XX Century is enormous. But so is his influence on the XIX and XVIII Centuries.

So, what's particular of the XX Century and who influenced those particularities the most?
I propose three candidates: Vladimir Illich Ulianov (AKA Lenin), John Maynard Keynes and Sigmund Freud. Without them, it's hard to understand the XX Century. None of them (specially Lenin) will have such an impact on the XXI Century.

Here's an interesting attempt at making an ordered ranking.

The 100: A Ranking of the Most Influential Persons in History
Revised and Updated for the Nineties
by Michael H. Hart

http://www.mind.net/dlmark/hundred.htm

The list is in order from 1st to 100th (followed by runners up!)

The idea of Gutenberg as encapsulated in popular culture
as the font of mass communication is a reasonably good choice
but I too think that if its impact on the 20th century (even though it predates it) qualifies, that there are alot more important building blocks below it, like the domestication of grain for instance, without which population levels in the 20th, 14th or 2 century wouldnt be possible

as far as Gutenberg himself goes
he got the credit for a much older technology (China 868 AD)
and there is some debate (Coster of Haarlem) as to the true Western inventor

like most technologies, it needs to be in the right place at the right time to be widely adopted, there are a great number of inventions that for one reason or another are ignored (Gallo-Roman reaping machine for instance) without the emergent merchant class to consume the books, it too would have been a failed technology, with the need, "who" was just a matter of time

in the 20th century, consider theseachievements,
http://www.greatachievements.org/greatachievements
1. Electrification
2. Automobile
3. Airplane
4. Water Supply and Distribution
5. Electronics
6. Radio and Television
7. Agricultural Mechanization
8. Computers
9. Telephone
10. Air Conditioning
and Refrigeration
11. Highways
12. Spacecraft
13. Internet
14. Imaging
15. Household Appliances
16. Health Technologies
17. Petroleum and
Petrochemical Technologies
18. Laser and Fiber Optics
19. Nuclear Technologies
20. High-performance Materials

looking at Electrification as a building block for much of the rest
Id nominate Nikola Tesla for AC Current, without which widespread distribution of electricity wouldnt be economical

Ice Czar: Good choice. A lot of people forget him because of the fame of his contemporaries such as Edison whom Tesla considered a tinkerer.

I nominate Albert Einstein as the most influential person... perhaps of any century.

Einstein is not only responsible for Nuclear power and the Atom Bomb... his theories are also crucial to our understanding of the Universe and even the development of semiconductors (which give you the ability to read this message now).

Indirectly, much like Newton is responsible for the moon landing
Neils Bohr, Werner Heisenberg and the rest of the Quantum Mechanics crew holds a far stronger claim to the implemented nuclear age than the predictive E = mc², Einstein was some say myoptically focused on the macro scale
blind to the actual implementation on the microscale


Einstein was at best dimly aware of Weak Nuclear Force, and chose to ignore Quantum Mechanics with the Strong Nuclear Force and actual experimentation, and was thus left behind in his later life in his attempts to develop a Unified Field Theory with Just Electromagnetism and Gravity

well worth the bandwidth
http://www.pbs.org/wgbh/nova/elegant/program.html

Id also point out we dont have a large scale nuclear society
industry is primarilly fossil fuel and electromagnetic
even the limited nuclear production that is online, is translated to the electromagnetic for energy distribution

I guess it could be argued that John D Rockefeller and the other oil barons could be the most influential persons on what is still larely our fossil fuel economy

what Id like to be able to say in the near future, is that
Sir William Robert Grove, is the most influental person on the 21st century